I've had similar training back in the day. This was when my employer (Nokia) was making Linux based phones and they needed to educate their engineers on what was and wasn't legally dodgy to stay out of trouble. Gplv2 was OK with permission (with appropriate measures to limit its effect). Particularly with Java, you had to be aware of the so-called classpath exception Sun added to make sure things like dynamic linking of jar files would not get you into trouble. Permissive licenses like Apache 2.0, MIT, and BSD were not considered a problem. GPLv3 was simply a hard no. You'd get no permission to use it, contribute to it, etc.
Apple, Nokia, and many other large companies, employ lawyers that advice them to steer clear of things like GPLv3. The history of that particular license is that it tried to make a few things stricter relative to GPLv2 which unintentionally allowed for things like commercial Linux distributions mixing closed and open source. That's why Android exists and is Linux based, for example. That could not have happened without the loopholes in GPLv2. In a way that was a happy accident and definitely not what the authors of that license had in mind when they wrote the GPL.
It's this intention that is the problem. GPLv3 might fail to live up to its intentions in some respects because of untested (in court), ambiguous clauses, etc. like its predecessor. But the intention is clearly against the notion of mixing proprietary and OSS code. Which, like it or not, is what a lot of big companies do for a living. So, Apple is respecting licenses like this by keeping anything tainted by it at arms length and just not dealing with it.
As someone on the Networks side, I had the pleasure to write multiple Excel files with all the dependencies of our product listing all the relevant facts for every single jar file.
Apple, Nokia, and many other large companies, employ lawyers that advice them to steer clear of things like GPLv3. The history of that particular license is that it tried to make a few things stricter relative to GPLv2 which unintentionally allowed for things like commercial Linux distributions mixing closed and open source. That's why Android exists and is Linux based, for example. That could not have happened without the loopholes in GPLv2. In a way that was a happy accident and definitely not what the authors of that license had in mind when they wrote the GPL.
It's this intention that is the problem. GPLv3 might fail to live up to its intentions in some respects because of untested (in court), ambiguous clauses, etc. like its predecessor. But the intention is clearly against the notion of mixing proprietary and OSS code. Which, like it or not, is what a lot of big companies do for a living. So, Apple is respecting licenses like this by keeping anything tainted by it at arms length and just not dealing with it.